Joint fluid exudation

Introduction After synovial injury of the knee joint, the synovial membrane showed hyperemia, edema and neutrophil infiltration. Synovial vasodilation, plasma and extracellular osmosis, produce a large amount of exudate, while synovial cells are active, producing a large amount of mucin. The exudate contains red blood cells, white blood cells, bilirubin, fat, mucin and cellulose. In severe cases, the joint effusion is bloody. Joint swelling and limited mobility.

Cause

After the joint is infected, it first causes synovitis, synovial edema, congestion, and exudate. The amount and nature of the exudate depends on the size of the bacterial toxicity and the strength of the patient's resistance. According to different degrees and different stages of synovitis, different joint exudates are present.

an examination

Related inspection

Synovial fluid routine examination of joint cavity fluid examination synovial fluid routine examination joint examination arthroscopy

(1) Serous exudate: synovial swelling, hyperemia, leukocyte infiltration, increased exudate, and clear synovial fluid. If the patient has strong resistance, the bacteria is less toxic, and the treatment is timely, the exudate is gradually reduced and healed, and the joint function can return to normal. Improper treatment, although sometimes showing a temporary improvement, and then relapse, or further worsening, the formation of serous fibrin or purulent exudate.

(2) Serum fibrinous exudate, the degree of synovitis is intensified, the synovial membrane is not only congested, but also has more obvious inflammation. Some fibrin is formed on the synovial surface, but the articular cartilage surface is still not tired. The joint fluid is flocculent. Containing a large number of granulocytes and a small number of monocytes, the bacterial culture is mostly positive. There is also inflammation around the joints. Although it can be controlled in this period, it is easy to cause joint adhesion and a certain degree of joint function loss.

(3) Purulent exudate: It is the most serious type and stage of acute arthritis. The infection quickly spreads to the entire joint and surrounding tissues, and there is a lot of pus in the joint. Joint capsule and synovial membrane are swollen, hypertrophic, leukocyte infiltration, and local necrosis. Articular cartilage is dissolved soon, which is caused by the dissolution of the articular cartilage surface by the action of proteolytic enzymes released by dead white blood cells in the pus. Accumulation of the joints in the joints and increased pressure can destroy the ligaments and joint capsules causing perforation, causing cellulitis or abscess formation in the soft tissues around the joints, and even piercing the skin and forming the sinus. It is difficult to treat and can be cured for a long time. Even if healed, the joint often undergoes fibrous osteogenesis.

Differential diagnosis

Generally no obvious precursor symptoms, rapid onset, general malaise, fever, joint pain, swelling, limited mobility. If the possibility of septic arthritis is suspected, intra-articular puncture should be performed immediately, and the joint fluid should be taken out for smear examination and bacterial culture.

The severity of symptoms of septic arthritis varies according to the pathological changes of joint synovitis. If the exudate is serous, the joint swelling is only moderate, the pain is not significant, the local is slightly burning, and the superficial joint may have a sense of fluctuation. Many joints cannot be fully extended, and other directions have different degrees of activity limitation. The whole body reaction is not big. When the exudate is serous fibrin, all symptoms are exacerbated. When purulent exudate, the whole body is toxic, chills, high fever up to 40-41oC, pulse acceleration, white blood cell count can be increased to more than 2,000, and the blood sedimentation rate increases. The joints are painful and unable to move. Local redness, swelling, heat and tenderness. Because there are more empyemas in the joints, and the surrounding soft tissue inflammation causes protective muscle spasm, the joints are in a deformed position, and contracture occurs soon, causing pathological subluxation or total dislocation of the joints, especially in the hip and knee joints. It is easy to happen. If the pus penetrates the joint capsule to the soft tissue, the pain is slightly relieved due to the reduction of intra-articular tension. However, if the drainage is not obtained, the local and the body can not be improved.

If the skin is worn, the sinus is formed, and it develops into chronic septic arthritis after prolonged healing. Suppurative arthritis is difficult to diagnose early in infants. The hip joint is the main site of the disease, and generally has symptoms such as high fever, hip pain, local swelling and limited limb function. However, the symptoms of the newborn are not obvious. For example, the restlessness in the newborn, the crying of no cause and the inactivity of the affected limb should be highly suspected.

The disappearance of the femoral head is the final result of hip suppurative infection in children and cannot be regenerated. In the X-ray examination, the joint capsule was swollen in the early stage due to the increase of joint fluid, the gap was widened, and the bone end gradually decalcified. If the articular cartilage is damaged, the joint space is narrowed. Sometimes it can be said to have osteophyte spondylolisthesis or pathological dislocation. In the later stage, the bone under the joint surface is reactive hyperplasia, osteosclerosis, and increased density. Finally, the articular cartilage is completely dissolved, the joint space disappears, and it is bony or fibrous, or the disease is dislocated.

In general, adolescents and adults often develop bones due to destruction of articular cartilage, and children often suffer from bone destruction and absorption, causing pathological dislocation.

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